Generally, a computing device (e.g., a computer) can be conceptually reduced to a device that can accept content (or information) typically as data in a digital or binary form and manipulate it to obtain or determine a result based on a sequence of instructions (or computer program) that effectively describes how to process the data. More complex computers can store content including the computer program. A computer program may be invariable and/or built into the computer device as logic circuitry provided, for example, on microprocessors or computer chips. Today, general purpose computers can have both kinds of programming. Given the prevalence of computing devices in modern society, computer storage or computer memory used to store content, is often casually referred to as “memory.” Storing content (or information retention) is of one the core functions of computing devices. As such, memory is one of the fundamental components of all modern computers and is often coupled with a Central Processing Unit (CPU) to implement the basic Von Neumann computer model which has been used since the 1940s.
Today, numerous types of computing devices are available. These computing devices widely range with respect to size, cost, amount of storage and processing power, from the expensive and powerful servers, relatively cheaper Personal Computers (PC's) and laptops, to more inexpensive microprocessors or computer chips provided in automobiles and household electronic appliances.
In recent years, portability and mobility of computing systems have improved. Today, various mobile and handheld computing devices including wireless phones, media players, Personal Digital Assistants (PDA's) are widely available. Generally, a handheld device (also known as handheld computer or simply handheld) can be a pocket-sized computing device, typically utilizing a small visual display screen for user output and a miniaturized keyboard for user input. In the case of a Personal Digital Assistant (PDA), the input and output can be combined into a touch-screen interface. Along with mobile computing devices (e.g., laptops, smartphones), PDAs and media players are becoming increasingly popular.
As suggested above, memory and memory devices have long been an important part of computing and computing devices. Memory technology has also markedly improved in recent years. Today, relatively large amount of content can be stored n a portable and easy to access devices such as USB flash drives (or USB flash devices). The content stored on USB flash drive can be easily carried and copied on various computing devices. By way of example, data stored on server computer can be copied on a USB flash drive and taken home and loaded (or copied) on a Personal Computer (PC) and used. The data can be modified on the PC and stored back on the USB flash drive. The USB flash drive can be taken back to work to be used by a computer provided at work or carried to a different city and used by another computer or laptop. The USB flash drive is especially popular today and represents an exemplary advancement in storage technology which has effectively improved portability and mobility of computing systems. As such, USB flash drives will be discussed below.
USB flash drives are generally NAND-type flash memory data storage devices integrated with a USB (universal serial bus) interface. NAND flash architecture was introduced by Toshiba in 1989. NAND flash memories are typically accessed much like block devices such as hard disks or memory cards. The pages are typically 512 or 2,048 bytes in size. Associated with each page are a few bytes (typically 12-16 bytes) that should be used for storage of an error detection and correction checksum. USB flash drives are typically small, lightweight, removable and rewritable. Memory capacities for USB flash Drives currently can range from 32 megabytes up to 64 gigabytes. Capacity is limited only by current flash memory densities, although cost per megabyte may increase rapidly at higher capacities due to the expensive components. USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They are more compact, generally faster, hold more data, and are more reliable (due to both their lack of moving parts, and their more durable design) than floppy disks. These types of drives use the USB mass storage standard, supported natively by modern operating systems such as Windows, Mac OS X, Linux, and Unix.
Generally, a flash drive has a small printed circuit board typically in a plastic or metal casing, making the drive sturdy enough to be carried about in a pocket, as a key fob, or on a lanyard. The USB connector protrudes from the casing, and is usually covered by a removable cap. Most flash drives use a standard type-A USB connection allowing them to be connected directly to a port on a personal computer.
To access the data stored in a flash drive, the drive is typically connected to a computer, either by plugging it into a USB host controller built into the computer, or into a USB hub. Typically, flash drives are active only when plugged into a USB connection and draw all necessary power from the supply provided by that connection. However, some flash drives, especially high-speed drives, may require more power than the limited amount provided by a bus-powered USB hub, such as those built into some computer keyboards or monitors. These drives will not work unless plugged directly into a host controller (i.e., the ports found on the computer itself) or a self-powered hub.
The advancement in memory devices and mobile computing is generally appreciated by those skilled in the art as well as the general public. However, computer security remains as a major concern. Accordingly, techniques for improving the security for computing systems are needed.